Its scientists altered the structure of sugar so that it dissolves more quickly.

This fools the taste buds, with the effect of raising the sweetness, claims Nestle.

The company”s chief technology officer, Stefan Catsicas, described the work as “truly groundbreaking research”.

“Good science”

It”s hard to generalise about how much sugar is in chocolate.

But milk chocolate is typically 50% sugar – some of which comes from the milk used.

White chocolate could be as much as 60% sugar.

The amount of sugar in dark chocolate is highly variable. It can be as much as 40%, but it can have no sugar in it at all, although most people would consider that much too bitter.

Professor Julian Cooper, an independent food technology consultant, said Nestle”s development was important: “This is good science. A lot of people have been looking at sugar trying to reduce the amount.”

He said this would give Nestle products that use the adapted sugar the “halo-effect”, in that people may think they can eat more.

“Double-edged sword”

But Professor Cooper, who has worked in sugar for 40 years, also said news Nestle was patenting the method could spur on its rivals” own attempts to cut the sugar without the taste: “A patent is a double-edged sword. Although it protects what you have done it also tells your rivals about it.”

Nestle has been cutting sugar across its range of products since 2007 when it introduced a “global policy on sugar reduction”.

Other food companies have made technological breakthroughs with ingredients. Six years ago, PepsiCo, which owns the Walkers crisp brand, developed a designer salt molecule that it said would allow it to use less sodium without affecting taste.